Up to 70 percent of the human body consists of water - it exists both inside and outside the body's cells. Blood is mostly made up of water, as are organs and muscles. Water retention (or fluid retention) refers to an excessive build up of fluid in the circulatory system, body tissues, or cavities in the body.

A complex system of hormones and prostaglandins (hormone-like substances) are used by the human body to regulate water levels. This means that excess water can be excreted quickly from the kidneys in the form of urine. Likewise, if we drink less fluid, there will be less urine produced.

Water retention can occur in many different areas of the body and for different reasons. We will look at these individually.

Causes of water retention

There are many possible causes of water retention, including the following:

Capillaries

Fluid rich in nutrients, vitamins, and oxygen continuously passes from tiny blood vessels (capillaries) into surrounding tissues - this fluid is known as interstitial fluid.

Interstitial fluid nourishes cells and eventually makes its way back to the capillaries. Water retention may occur if the pressure inside the capillaries changes.

Water retention is also possible if something occurs that makes the capillary walls too leaky. If something goes wrong with pressure or the wall becomes too leaky, excess liquid will be released into the spaces between cells.

If too much fluid is released, more of it will remain in the tissues, rather than returning to the capillaries, resulting in swelling and water retention.

The lymphatic system

The lymphatic system drains fluid from tissues (called lymph) and empties it back into the bloodstream. However, if too much fluid is released in the first place, the lymphatic system can be overwhelmed - it is unable to return fluid fast enough, and it accumulates around the tissues.

Sometimes, if the lymphatic system is congested, the rate at which fluid is returned to the bloodstream may change. This means that fluid might remain in the tissues, causing swelling in various parts of the body, including the abdomen, ankles, legs, and feet.

The heart

Normal pressure within blood vessels is partly maintained by the pumping force of the heart. However, if the heart starts to fail, there will be a change in blood pressure, which often results in serious water retention.

Typically, the legs, feet, and ankles will swell. Fluid will also build up in the lungs, giving the patient a long-term cough and/or difficulty breathing.

Congestive heart failure can eventually cause breathing problems, as well as excessive stress on the heart. The patient will probably be prescribed diuretics. A diuretic is anything that promotes the formation of urine by the kidney - in other words, anything that helps the body shed water.

The kidneys

Blood is filtered in the kidneys - waste, fluids, and other substances are extracted and cross into tiny tubules; from there, the bloodstream reabsorbs anything the body can reuse. What the body cannot reuse - waste - is excreted in urine.

In most cases, kidneys can eliminate all waste materials that the body produces. However, if the blood flow to the kidneys is affected, problems can occur. For instance, in kidney failure, waste material, including fluids, cannot be eliminated from the body properly, resulting in fluid retention.

Pregnancy

The weight of the uterus on the major veins of the pelvis can cause a build-up of fluid in the body during pregnancy. In most cases, it is nothing to worry about and generally resolves after the baby is born.

Physical inactivity

Physical inactivity can sometimes cause water retention.

Exercise helps the leg veins return blood to the heart. If the blood does not travel fast enough, it will begin to accumulate in the legs, resulting in higher pressure in the capillaries. Fluid will leave the capillaries at a higher rate because of the higher pressure.

The higher pressure also makes it harder for fluids to come back later on.

Exercise is necessary to stimulate the lymphatic system to carry out its function of regulating overflow - bringing fluids back into the bloodstream at rates that may regulate body water levels. Very long periods of physical inactivity, such as a long-haul flight, increase the risk of water retention.

During a long-haul flight, even minor physical movements, such as standing up on tiptoes a few times, rotating the ankles, and wiggling the toes can help reduce fluid retention.

Protein

Humans require a certain level of proteins for effective water balance. An individual with severe protein deficiency may find it harder to get the water from the tissue spaces back into the capillaries. The enlarged abdomen of someone who is starving is mainly caused by a lack of protein in their diet.

Histamine

When inflammation is present in the body, histamine is released. Histamine causes the gaps between the cells of the capillary walls to widen, making them leakier. The aim is to make it easier for infection-fighting white blood cells to quickly get to the site of an inflammation. However, if the inflammation persists for a long time, water retention can become a problem.

Pre-menstrual water retention

Pre-menstrual water retention can cause bloating and breast tenderness. Experts say this is due to hormone imbalances and some nutritional factors:

Malnutrition and bad diet - a poor diet low in protein result in low levels of albumin, which may also play a part in developing water retention.

Salt (sodium) - sodium-rich foods may cause water retention.

Allergies - some foods and insect bites may cause edema in susceptible people.

Thyroid disease - people with a disorder of the thyroid gland commonly experience water retention.

Treatments for water (fluid) retention

Treatment for water retention depends on several factors, including the root cause.

Treatment for leaky capillaries

In this case, tissues are retaining both water and protein. Diuretics would cause the kidneys to remove fluid faster from blood, while protein in the tissue spaces would continue drawing fluid from blood into tissues - resulting in dehydration of the blood. Eventually diuretics can actually make water retention worse.

A doctor will treat the cause of the leaky capillaries. As they are often linked to a protein problem, medications will be given that help break up the protein in the tissue space.

It can be difficult for a doctor to distinguish between leaky capillaries and non-leaky capillaries water retention.

Reducing water retention symptoms

The following remedies may reduce the symptoms of water retention:

Reduced salt consumption.

Weight reduction.

Regular exercise.

Raising the legs several times per day to improve circulation.

Wearing supporting stockings if the water retention occurs in the lower limbs.

Avoiding sitting and standing still for too long.

Walking regularly when traveling by car, train, boat, or plane.

Avoiding extremes of temperature, such as hot baths, showers, and saunas. Dressing warmly if it is cold.

Massage - if the affected area is stroked firmly in the direction of the heart, it may help move the fluid. It is important that the hand movements do not cause pain.

As a christian I practise a spiritual act of fasting food sometimes and water for about ten or so days praying.After that I normally have retention on my legs which disappears after a week or two,but i do such fasts twice/three times a year with several months spacing,but this time my left leg has normalised and my right still swollen its now more than three weeks and the back of my swollen leg and the knee area are in pain,will you advise ?do i need to see a doctor?possibly developing DVT?problem imy my right side has suffered strain due to child birth over the years,this makes it vulnerable,what if wrong treatment is given .what will be the possible complications.

I believe you left out a couple of main reasons for water retention. The first of these is Venous Insufficiency which is basically when the Capillaries are to small to pump the water back up to the heart and or kidneys, The second of these is Lymphodema which is a different problem all together and one that not to many doctors are able to understand. This is with the exception of those except for ones in the European countries where they have been studying this for quite a long time and have found that with specific massage done by "Trained" therapists and with wraps from what is very close to a elastic bandage it can be controlled very well. People also misdiagnose the second as being the first of the two but is easily determined by applying some pressure to the affected area and when you see the skin color change from the flesh color to white because you are pushing the blood away from the area and once you take the pressure away if the coloring comes back right away then there is no problem with the veins and the movement in them, it would then be the first Venous Insufficiency because there would at that time seem to be an issue with the blood flow returning to the area.

I've been experiencing severe retention in my left thigh and hand (middle finger), resulting in a painful knee and finger joints. I have been diagnosed as hypothyroid, am on HRT, 70 yrs, possible benign growth on thyroid, recent weight gain of water ~17 lbs in the last three months. I've had sonograms, cat scans, xrays, echo cardiagram--to no avail. Am now experiencing difficulty walking. Don't know what else to do. Any suggestions???

I have had IBS since I was a baby diagnosed in 2003 and that it went back that far. (I would add I had to pay for this as a few months previously a professor at top hospital said was all in my mind as blood test RAST showed nothing).

I have had allergies and intolerances all my life although blood tests do not show this. I have had joint muscle pains for again since I was young and in my legs and that was put down to growing pains.

I have had at times had seven weeks of constant bowel pain sickness cramps etc. Several times I have put on three stone in a few months and then I would eat anything and everything as my body craved I know not what.Then something would happen and would lose all the weight to below seven stone.

On one occasion I bled profusely on my last period when I 49 years and I had a blood transfusion and could barely walk or breathe for months and always reckon that has not helped my legs and right lung since also they had let me walk around for a week with 4.1 HG reading, because they had not done a simple blood test in the hospital.

I am in this position again, except more worryingly I have water retention and my dr does not want me on the tablets too long. I come off them and I will put on half a stone overnight. I have severe pains in joints and muscles.

I am used to all the body pains as lived with them but the IBS is bad and could be colitis. I have to be honest had enough. I am under a specialist who is supposed to be tops, but he is a gastroenterologist and he is for the IBS and not happy I have not had certain procedures done recently since 1986, although have seen other specialists and my dr and all have refused an endoscopy which I wanted.

They found bacterial ulcers and did not treat them. I think the food that I eat after a very strict diet but that ended up not doing my IBS or me any good. Now I have a diet that is normal and think this may be the problem to retention. I itch all over. I am at the moment up and down and very sensitive. This is not in my head like I have always been told its a real proble.

For IBS I am on buscopan, citropalm diazepan zantac. They have helped and the first time I was given medication for it was two years ago before that I did alternative trying to get help as no one wanted to know in this country. I have spent in excess of £40000 in 30 years.

I am now 66 years old. Every day I get up stiff unwell. I am sure the liver cannot cope because if I was not well and not eat because of it I would be able to eat something I could not normally touch until it had built up again. I hope it is now not too late.

I was on 500mg of amoxocylen (something like that) for sinus that would not go in June and I had no pains no swelling and could eat so much. The water retention worries me when like today I am over half a stone lighter than yesterday morning.

I have severe pain and my hands like yesterday hurt and itch at same time and very hot. The toes are better than the other day. I have an idea what is happening as have had to look after myself for nearly 60 years with this as no one wanted to know. Please can you advise re the water retention which worries me. I am told I have arrhythmia but ECG for 15 seconds shows nothing but my pulse is erratic and my chiro said it is the bottom valve getting stuck.
Thank you Jane
Trust me this is not in my head.

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